virtdomains: userid?

[Bill Kearney]

Would this help your reverse DNS lookup trouble?  Or will using the
unqualified name still trigger a reverse lookup?

It doesn't appear to help my situation, in that I'd like logins without a
qualified name to use just the bare username and NOT append a realm onto it.
Is this possible?

-Bill
Configuring Virtual Domains

Introduction

    Virtual domains is the practice of hosting a service for more than one
    domain on one server. Cyrus IMAP has the ability to host IMAP/POP
    mailboxes for multiple domains (e.g. test at example.com and
    test at example.net) on a single server or Murder.

    In order to accomplish this, Cyrus needs to know which domain to look
    in when a mailbox is accessed. There are two ways in which Cyrus can
    determine the domain:

      * Fully qualified userid - the client logs in with a userid
        containing the domain in which the user belongs (e.g
        test at example.com or test%example.net)
      * IP address - the server looks up the domain based on the IP address
        of the receiving interface (useful for servers with multiple NICs
        or using IP aliasing)

    Both of these methods are active if the virtdomains option is set to on
    (or yes, 1, true) and can be used in conjunction with one another. If
    the virtdomains option is set to userid, then only the first method is
    used. Note that a fully qualified userid takes precedence over a domain
    obtained from the IP address.